Piston



'July 1 5 1930- c. E. SUMMERS PISTON Filed Ma 11-, 1927 Patented Julyis, 1930 UNITED STATES PATENT OFFICE CALE.'B IE. SUMMERS, OI PONTIAC,MICHIGAN, ASSIGNOR TO GENERAL MOTORS COR- PORATION, OF DETROIT,MICHIGAN, A CORPORATION OIPDELAWARE PISTON Application filed Kay 11,

This invention relates to pistons for internal combustion engines usedon automotive vehicles. 7

' It is the object of the present invention to construct a two-piecepiston having ahead portion of one kind of metal and a skirt portion ofa different kind. The metal for the head portion is preferably onewhichis of relative light weight and which, at the same time, has a goodthermal conductivity, while the metal for'the skirt portion hasrelatively large wear resisting qualities and also a relatively For thehead of the piston'I preferably use '1 aluminum and forthe skirt portiona progerly alloyed and heat treated-steel is to preferred.

Inasmuch as two kinds of metal are used, they will have difierentcoeificients of expan-" sion and I accordingly design the two parts forman inwill be so proporsurface will be in regardless of the so that theirmeeting edges will clined surface and they tioned that this meeting firmcontact at all times,

temperature to which the istonis subjected during the operation of tileengine. The head of the piston is provided with two downwardlyprojecting webs, at the end of which I form bearing boxes for thereception of the pin of the connecting'rod. The skirt portion isprovided with openings having boss formations which are concentric withthe bearing boxes and intO'which the ends of the piston pin is'received.

The head of the piston is castand in order to unite the skirt portion tothe head portion. I provide two brackets about which the head is cast sothat they form a substantially integral structure therewith. Thesebrackets project laterally from the bearing boxes and have flanged endsto which the skirt portion is secured, for example, by welding.

As a modification I may cast'the head portion into the skirt portionandprovide flanges 1 .on the skirt around which themetal of the.

parts rigidly together.- I may also provide and into which formationsthe cast metal may low thermal coeflicient of expansion. I

" head is hollow,

'piston rod to the piston 10.

properly dovetailed formations on parts of the skirt;.

1927. Serial No. 190,5 59.

flow in order to secure a more intimate connection between the head andskirt ortion.

' he invention is disclosed in t e accompanying drawing in which: ig. 1is a view in elevation of a piston constructed in accordance with myinvention with parts shown in sectionfor purposes of clearerillustration. Fig. 2 is a section on the line 22 of Fi 1. Fig. 3 is asection on the lines 3-3 of lgs. 1 and 2.

' Fig. 4 is a sectional view of a modification. Fig. 5 is a-sectional'view on the line 5-5 of Fig. 4. Referring to the numbered parts on thedrawing, 10 indicates-my improved pistonas a whole, 11 is the upper partor head portion, and 12 the lower part or skirt portion.

he head is cast of a metal which preferably has a good thermalconductivity and at the same time is relatively light in weight,

which strengthens the entire structure. The I except for the rib l6, which makes for a very light structure.

The ends of the webs 14 and 15 terminate in enlarged portion'sT formingboxes 17 and 18, having openings 19 and 20, respectively, for thereception of the pin which pivots the By referring to Figs. 1 .and'2' itwill be noted that the head hasan inclined surface at 21 which extendsaround the periphery and the purpose of which will be laterde-v scribed.p At the time of-the casting of the cylinder. head 11 a pair of.brackets 22 and 23 are positioned in the mold so that the box portionsat the ends of the webs 14 and- 15 will embed the brackets so as to makethem substantially integral with the piston head.

Thesebrackets have central openings as at 24 head may be cast in orderto hold the two conforming to the openings 19 and 20 of the boxes 17 and18 to allow for the passage of the connecting bolt an'd theseopeningsare. flanged so as to obtain a close contact between the head and thebrackets and to more from a blank and later rolled into its finishedshape for assembly with the head portion. The skirt has the stiffeningribs 26 and at its meeting place with the head 11 it has an inclinedflanged edge 27, complementary to the inclined edge 21. The constructionof the head 11 and skirt 12 is such that when the heating of the pistontakes place during the operation of the engine, the difference in thecoefiicients of expansion of the two metals is such that a tight contactbetween the surfaces as 21 and 27 will be maintained at all times.

At the meeting edges of the skirt portion when rolled together Ipreferably provide tabs 28 which may be welded together to hold theskirt in its circular form. The entire seam may also be welded ifdesired.

The skirt is attached to the head structure by means of the flanges 25on the ends of the brackets 22 and 23. By referring to Fig. 3 it will benoted that these flanges conform to the circular shape of the skirt asshown I at 29 and at which meeting surfaces the skirt and bracket areunited by any suitable means, welding being preferred.

The skirt is also provided with two openings 30 and 31', having inwardlyextending bosses 32 and 33, which conform to and are concentric with theopenings 19 and 20 of the piston head 11. By referring to Figs. 2

of the bearing surfaces.

and 3 it will be noted that there is a close contact as shown at 34between the bosses 32 and 33 and the bearing boxes 17 and 18.

The species of Figs. 4 and 5 diflers from that of Fi s. 1 to 3 in thatthe head 11 is cast into t e skirt portion 12. The downwardly extendingwebs 14' are cast into the dovetailed portions 35 of'inwardly bent tabs36 on the skirt 12 to give a close contact and insure a more intimateconnection between the head 11 and skirt 12'. species the bosses 32' and33 are surrounded by the cast metal from the head 11 forming a structurewhich is substantially integral and which is very ri 'd.

In all species, the bbttom of the skirt portion is inturned as at 37giving a rounded edge as shown at 39.

I claim: 1'

1. In a piston, a head portion, bearing "members in said head havingbearing surfaces, a skirt portion abutting and forming a continuation ofsaid head, and bosses on' said skirt in alignment with said bearingmembers, said bosses forming a continuatio .2. In a'two part piston, anupper part, a

I plurality of-webs extending'from'said upper part,bearing boxes at'the.end of said webs,

In this said boxes having bearing surfaces, a lower part, bearing boxesat the end of said webs,

said boxes having bearing surfaces, a lower part surrounding said websand bearing boxes, bosses on said lower portion concentric with saidboxes,'said-bosses forming a continuation of said surfaces, means tosecure said parts together, and a single inclined'peripheral edge oneachsaid head and skirt, said edges complementary to each other andforming the sole peripheral contact.

4. In a two part piston, an upper part, a plurality of webs extendingfrom said upper part, bearing boxes at the end of said webs,

said boxes having bearingsurfaces, a lower part surrounding said websand bearing oxes, bosses on said lower portion concentric with saidboxes, said bosses forming a continuation of said surfaces, means to se;cure said parts together, and a single inclined peripheral meeting edgeon each of said head and skirt, said edges complementary to eachotherand forming the sole peripheral con tact, said inclined surfaces beingsuch that the relative expansion of the metals of the head and'of theskirt will keep the two parts in firm contact at all times.

5. In a two part piston, a skirt portion, a head portion cast into saidskirt portion, bearing portions. formed on said head portion, and bossesand'tabs on said skirt portion into which said head is cast, said bossesarranged concentric with said bearing portions and said tabs positionedcircumferentially below and spaced from said bosses.

6. 'In a piston, a plurality of separate brackets, a head portion castabout a portion of said brackets, a skirt portion formed sepafate fromsaid brackets and forming the lower end of said piston, said skirtportion secured to the ends of said brackets, said bracket portion insaid head having a flanged -or bent edge.

skirt portion secured to the ends' of said brackets, said bracketshaving their midpor-;

tions provided with bent edges to firmly hold them in the cast'head andtheir ends flanged .to afiord a securing means betweenthe piston andskirt.

8. In a piston, a cast head portion, an inclined or tapered peripheralor circumferential edge at the lower-most circumferential portion ofsaid head, a skirt portion secured to said head, and an inturnedinclined flange on the upper end of said skirt, said flange abuttingwith and conforming to said inclined or tapered portion of said head.

9. In a piston, a cast head portion, an inclined or tapered peripheralor circumferential edge at the lowermost circumferential portion of saidhead, a skirt portion, a plurality of brackets having said head portioncast about their mid portions, said brackets extending away from theircast connection and secured to said skirt at their ends, and an inturnedinclined flange on the upper end of said skirt, said flange abuttingwith and conforming to said inclined or tapered portion of said head.

In testimony whereof I afiix my signature.

' CALEB E. SUMMERS.

